The present invention relates to the manipulation of selected objects and, more particularly, to a robotic system in which objects are selectively picked from one location and placed in another location. The present invention is particularly well-suited for picking and placing objects held in a closely spaced array of similar objects. Test tubes, for example, are often stored or temporarily held in a tray including an array of closely spaced test tubes of like size. The object manipulator of the present invention may be utilized in an object manipulation system to move selected test tubes to and from the array of closely spaced tubes.
In accordance with one embodiment of the present invention, an object manipulator is provided including a gripper assembly arranged to grip and release an object. The gripper assembly comprises a plurality of gripper fingers, a gripper finger pivot assembly, and a finger spreader. Each of the gripper fingers includes a camming surface portion, a bearing surface portion, and an object engaging portion. The gripper finger pivot assembly is arranged to accommodate respective bearing surface portions of the plurality of gripper fingers. The finger spreader is positioned to progressively engage respective camming surface portions of the plurality of gripper fingers. The gripper fingers are shaped and the pivot assembly is arranged such that progressive engagement of respective camming surface portions by the finger spreader causes the object engaging portions to be drawn away from each other and such that progressive disengagement of respective camming surface portions and the finger spreader causes the object engaging portions to be drawn towards each other.
The camming surface portion, the bearing surface portion, and the object engaging portion may be arranged in succession along each of the gripper fingers. The object engaging portion may include a layer of object gripping material formed thereon. The bearing surface portion may be substantially straight.
The gripper finger pivot assembly may be arranged to define respective passages there through, and wherein the respective passages are arranged to accommodate respective bearing surface portions of the plurality of gripper fingers. The bearing surface portions of the plurality of gripper fingers may define a circular finger cross section and the respective passages may define a circular passage cross section slightly larger than the circular finger cross section. The respective passages may be defined by separate mating portions of the gripper finger pivot assembly;
A biasing member may be arranged to urge the object engaging portions towards each other. The biasing member may comprise a constrictive band arranged about the gripper fingers. The biasing member may be arranged to oppose progressive engagement of respective camming surface portions by the finger spreader.
The plurality of gripper fingers may be shaped such that, upon progressive engagement of the camming surface portions by the finger spreader, a path of movement of the object engaging portions follows a path of movement of the camming surface portions.
The finger spreader may be arranged to initially engage the camming surface portions at a first cross sectional portion thereof and subsequently engage the camming surface at progressively larger cross sectional portions thereof. The first cross sectional portion and the progressively larger cross sectional portions of the finger spreader may be circular.
An axial stop may be provided against which the camming surface portions are arranged to rest upon disengagement of the camming surface portions and the finger spreader. The axial stop may define an axial stop cross section that is no larger than a cross section of an object to be manipulated. The axial stop may define a circular axial stop cross section. The finger spreader may be arranged to progressively engage and disengage the camming surface portions by moving along the axial stop.
A gripper finger bracket may be arranged along the gripper fingers between respective camming surface portions and respective bearing surface portions. The gripper finger bracket may be arranged to define respective finger bracket apertures through which respective gripper fingers move upon progressive engagement and disengagement of the camming surface portions by the finger spreader. The respective finger bracket apertures may define an arcuate shape.
In accordance with another embodiment of the present invention, an object manipulator is provided comprising a rotary turret assembly and a plurality of gripper assemblies. The rotary turret assembly defines a plurality of gripper assembly stations and a gripper pick/place position. The rotary turret assembly is arranged to rotate the gripper assembly stations about a turret axis so as to position a selected one of the gripper assembly stations in the pick/place position. The plurality of gripper assemblies are arranged in respective ones of the gripper assembly stations. The rotary turret assembly includes a gripper actuator assembly arranged to cause a gripper assembly positioned in the pick/place position to execute an object pick/place operation.
The plurality of gripper assemblies may be removably secured in respective ones of the gripper assembly stations. The gripper actuator may be arranged to remove a gripper assembly positioned in the pick/place position from one of the gripper assembly stations. The plurality of gripper assemblies may be removably secured in respective ones of the gripper assembly stations through magnetic coupling of the gripper assemblies and the gripper assembly stations.
Each of the gripper assemblies may comprise a plurality of gripper fingers and a finger spreader positioned to progressively engage respective camming surface portions of the plurality of gripper fingers. The gripper assembly may be arranged such that progressive engagement of respective camming surface portions of the gripper fingers by the finger spreader causes object engaging portions of the gripper fingers to be drawn away from each other and such that progressive disengagement of respective camming surface portions of the gripper fingers and the finger spreader causes the object engaging portions to be drawn towards each other. The gripper actuator may be further arranged to actuate a finger spreader of a gripper assembly positioned in the pick/place position following removal of the gripper assembly from one of the gripper assembly stations. The gripper actuator assembly may further comprise a spreader actuator arranged to engage a selected finger spreader and move the selected finger spreader along an axis parallel to the turret axis. The gripper actuator assembly may further comprise a Z-axis drive arranged to move a selected gripper assembly along a Z-axis parallel to the turret axis.
The object manipulator may further comprise a bar code reader secured to the object manipulator and defining a field of view encompassing the pick/place position.
In accordance with yet another embodiment of the present invention, an object manipulation system is provided comprising a plurality of objects arranged in an object plane, an X-Y positioner, and an object manipulator. The X-Y positioner is arranged to move within an X-Y plane displaced from and parallel to the object plane. The object manipulator is coupled to the X-Y positioner so as to be movable with the X-Y positioner. The object manipulator comprises a rotary turret assembly and a plurality of gripper assemblies. The rotary turret assembly defines a plurality of gripper assembly stations and a gripper pick/place position. The rotary turret assembly is arranged to rotate the gripper assembly stations about a turret axis so as to position a selected one of the gripper assembly stations in the pick/place position. The gripper assemblies are arranged in respective ones of the gripper assembly stations. The rotary turret assembly includes a gripper actuator assembly arranged to cause a gripper assembly positioned in the pick/place position to execute an object pick/place operation on one of the objects in the object plane.
Additional X-Y positioners may be arranged to move parallel to the object plane in the same work cell as the original positioner. In which case, additional object manipulators may be coupled to each of the additional X-Y positioners.
Accordingly, it is an object of the present invention to provide scheme whereby objects may be selectively picked from one location and placed in another location. Other objects of the present invention will be apparent in light of the description of the invention embodied herein.